The Evolutionary Conserved Oil Body Associated Protein OBAP1 Participates in the Regulation of Oil Body Size    

Abstract

A transcriptomic approach has been used to identify genes predominantly expressed in maize (Zea mays) scutellum during maturation. One of the identified genes is oil body associated protein1 (obap1), which is transcribed during seed maturation predominantly in the scutellum, and its expression decreases rapidly after germination. Proteins similar to OBAP1 are present in all plants, including primitive plants and mosses, and in some fungi and bacteria. In plants, obap genes are divided in two subfamilies. Arabidopsis (Arabidopsis thaliana) genome contains five genes coding for OBAP proteins. Arabidopsis OBAP1a protein is accumulated during seed maturation and disappears after germination. Agroinfiltration of tobacco (Nicotiana benthamiana) epidermal leaf cells with fusions of OBAP1 to yellow fluorescent protein and immunogold labeling of embryo transmission electron microscopy sections showed that OBAP1 protein is mainly localized in the surface of the oil bodies. OBAP1 protein was detected in the oil body cellular fraction of Arabidopsis embryos. Deletion analyses demonstrate that the most hydrophilic part of the protein is responsible for the oil body localization, which suggests an indirect interaction of OBAP1 with other proteins in the oil body surface. An Arabidopsis mutant with a transfer DNA inserted in the second exon of the obap1a gene and an RNA interference line against the same gene showed a decrease in the germination rate, a decrease in seed oil content, and changes in fatty acid composition, and their embryos have few, big, and irregular oil bodies compared with the wild type. Taken together, our findings suggest that OBAP1 protein is involved in the stability of oil bodies.

Arabidopsis Small Rubber Particle Protein Homolog SRPs Play Dual Roles as Positive Factors for Tissue Growth and Development and in Drought Stress Responses

“…In higher plants, LDs participate in cell proliferation in the seedling establishment stage by providing neutral lipids as carbon sources, while the cellular roles of LDs in postgermination growth are not well understood (Siloto et al, 2006). Studies on plant LD-associated proteins, including oleosins, caleosins, oil body-associated protein (OBAPs), and SEIPIN, have mainly focused on seed development and germination (López-Ribera et al, 2014;Cai et al, 2015). On the other hand, expression of Arabidopsis SRPs has been detected in postgermination tissues, including roots, leaves, and flowers (Fig.…”

Plant Lipid Droplets and Their Associated Proteins: Potential for Rapid Advances

“…However, they are substantially shorter (longest being 21 residues for caleosin 299 and 24 residues for steroleosin, both one-third the length of the oleosin hairpin), and the hairpin 300 residues are only mildly conserved among isoforms within the same and among diverse species 301 (Song et al, 2014;Pasaribu et al, 2016). Two of the proline resides in the caleosin hairpin loop 302 are not essential for LD binding (Muller et al, 2017 monoacylglycerol hydrolase (to be described), possess no long hydrophobic or predicted 358 membrane-insertion segment (Gidda et al, 2016;Lopez-Ribera et al, 2014;Shimada et al, 2014 …”

Lauric Acid-ModifiedNitrariaSeed Meal Composite as Green Carrier Material for Pesticide Controlled Release

“…e detailed functionalization and fabrication processes of LA-NSM composites are schematically illustrated in Scheme 1. As stated earlier, the surface of NSMs is covered by a number of inborn waxes, oils, and other impurities [19], making it difficult to be directly modified and to graft some new groups. Herein, we proposed a simple alkalipretreatment method to remove these impurities and make the hydroxyl groups of NSMs exposed [34].…”

“…In terms of their chemical components, the oil-body membranes consist of approximately 50% phospholipids, 40% membrane proteins, and about 2-10% glycoproteins [18], which are abundant in various functional groups like acyl, long-chain alkyl, phosphate, carboxyl, and amidogen groups. e hydrophobic groups like long-chain alkyls endow NSMs with partial hydrophobicity and acquire the oily molecules voluntarily by absorptive function [19]. As a result, the NSMs display intrinsic positive sorption capacity for oily substances and consequently can be used as an ideal alternative base material for the fabrication of oleophilic carriers.…”